1. Field of the Invention
The present invention relates generally to a navigation service, and more particularly, to an indoor navigation method and system using lighting.
2. Description of the Related Art
As the luminous efficiency of Light Emitting Diodes (LEDs) has improved, their price has decreased. The LED has recently entered the special lighting market, which includes portable devices, displays, vehicles, traffic lights, and billboards, and the general lighting market, which includes fluorescent lamps and incandescent electric lamps. Further, the interest in Radio over Fiber (RoF) technology, which is complementary to Radio Frequency (RF) technology, is increasing due to the lack of RF band frequency, the possibility of interference between several wireless communication technologies, the increase of security demands in communication, and the introduction of an ultrahigh speed ubiquitous communication environment of 4G wireless technology.
Visible light communication for delivering information by using a visible ray is safe in use, uses a wide band, and can be freely used without any restriction. Visible light communication can also accurately detect a reception range of information since a light arriving place or a light progressing direction can be seen. Thus, visible light communication has advantages in that it is reliable in terms of security and can be driven at low power in terms of power consumption. Accordingly, visible light communication can be applied to hospitals and airplanes in which the use of RF is restricted, and can be used in providing additional information using an electronic display board.
Additionally, visible light communication can be more efficiently used in combination with a communication system using other wired/wireless communication media. A visible light communication system for providing information using lighting inside a building in combination with power line communication based on a power line or a Wireless Local Area Network (WLAN) is being researched.
Meanwhile, a mobile communication terminal, such as a cellular phone or a smart phone, portable by a user now includes various convenient functions, such as, a message transmission/reception function, a wireless Internet function, a schedule management function, and a navigation function.
The navigation function using Global Positioning System (GPS), provides a current position of a user and path information to a desired target position. In general, the navigation function is implemented to provide a current position of a vehicle and path information when the vehicle is moving. However, recently, development of a navigation system for pedestrians using a mobile communication terminal, such as a cellular phone, a smart phone, or a Personal Digital Assistant (PDA), is being developed for pedestrians visiting a destination in a complicated downtown area or a strange area. A navigation system aimed at pedestrians provides an optimal path for arriving at a predetermined destination to a pedestrian having the navigation system, and allows the pedestrian having the navigation system to monitor a current position.
However, in the case of a conventional navigation system using GPS, if a pedestrian moves into a building or underground, the pedestrian may not be able to receive a GPS signal, so the pedestrian is unable to use a navigation service.
Accordingly, implementation of a navigation system indoors by installing an Access Point (AP) and using an RF signal has been attempted. However, a measurement error is large, and a large number of APs is required. Since an error in position information measurement is over 10 meters, the navigation system is too inconvenient to use. Further, in the use of an RF signal, the RF signal has difficulty transmitting between walls.